For an ABS you'll need scripts. To find scripts, google is your friend!
I'll show you how to install it however.
Open your script editor in RMVXA (you can do this by either going to "Tools>Script Editor" or just by pressing F11.
Once the script editor appears onscreen, turn your attention towards the box on the left. Scroll it down until you reach "Materials".
Click on an empty space between "Materials" and "Main Process". (You can create more 'empty spaces' with the insert key.)
Now that you have selected a location to place the script, copy the script you want and paste it onto the box on the right.
Press "OK" and save the project. Your script is now loaded.
As for scripts, there's so many out there. I prefer a front view battle system, so I use
Yanfly's Battle Engine Ace (Which requires his core engine, which can be found on his site.
As for side view battle systems,
Symphoria seems to be the rage.
And by Active time, do you mean a Legend of Zelda like system, or a FF6 like system?
